Book Image

Real-Time 3D Graphics with WebGL 2 - Second Edition

By : Farhad Ghayour, Diego Cantor
5 (1)
Book Image

Real-Time 3D Graphics with WebGL 2 - Second Edition

5 (1)
By: Farhad Ghayour, Diego Cantor

Overview of this book

As highly interactive applications have become an increasingly important part of the user experience, WebGL is a unique and cutting-edge technology that brings hardware-accelerated 3D graphics to the web. Packed with 80+ examples, this book guides readers through the landscape of real-time computer graphics using WebGL 2. Each chapter covers foundational concepts in 3D graphics programming with various implementations. Topics are always associated with exercises for a hands-on approach to learning. This book presents a clear roadmap to learning real-time 3D computer graphics with WebGL 2. Each chapter starts with a summary of the learning goals for the chapter, followed by a detailed description of each topic. The book offers example-rich, up-to-date introductions to a wide range of essential 3D computer graphics topics, including rendering, colors, textures, transformations, framebuffers, lights, surfaces, blending, geometry construction, advanced techniques, and more. With each chapter, you will "level up" your 3D graphics programming skills. This book will become your trustworthy companion in developing highly interactive 3D web applications with WebGL and JavaScript.
Table of Contents (14 chapters)

Reading Pixels from the Offscreen Framebuffer

We can now go to the offscreen buffer and read the color from the appropriate coordinates:

WebGL allows us to read back from a framebuffer using the readPixels function. As usual, having gl as the WebGL context variable within our context:

Function Description
gl.readPixels(x, y, width, height, format, type, pixels)
  • x and y: Starting coordinates.
  • width and height: The extent of pixels to read from the framebuffer. In our example, we are just reading one pixel (where the user clicks), so this will be 1, 1.
  • format: Supports the gl.RGBA format.
  • type:: Supports the gl.UNSIGNED_BYTE type.
  • pixels: A typed array that will contain the results of querying the framebuffer. It needs to have sufficient space to store the results depending on the extent of the query (x, y, width, height). It supports the Uint8Array type.

Remember that...